A mechanic told us we needed a new fuel pump when the 88 RX-7 died. We put the pump in but it still wouldn't start. Further checks found that there is no spark at the ignitor. We checked the impulse from the ECU and there is no impulse. Next we changed out the ECU.....still no impulse from the new ECU. The fuel pump works when it is tested by bridging the yellow test plug. Is there some correlation between the fuel pump and the ECU that would keep the ECU from emitting a pulse? What voltage is the ECU suppose to send to the sensors and to the ignitor/coil? Any information at all would help. Really need the car. Thanks.

 

Check the EGI fuses under the hood in the main fuse block by the driver side strut tower, then check the 'motor' fuse located under the dash, let me know what you find.

 

The ECU sends a pulsed neg trigger to the coils. You would need to set your digital multi-meter to read AC voltage, clip the positive input of your meter on the battery pos, and the neg lead of your DMM to the coil trigger lead.

It would show you AC voltage when the engine is being cranked and running.

I doubt though that it is really not working... unless the ECU itself has failed entirely (which you ruled out when you replaced it) or you have a blown EGI fuse.

Does your mechanic understand modern automotive electronics and RX-7s??? it doesn't sound like it if he is just replacing parts without really testing (like the fuel pump and ECU). Does he even have a DMM?

 

I checked the fuses, appear okay. Pulled out a plug and grounded it....no spark?? I'll try the AC pulse and see if the pulse is there. If it is, I guess the ignitor is bad? Ohm check of coil indicates okay. Don't think my mechanic friend knows that much about rotary motors.

Thanks

 

Check/replace the CAS if you're certain none of the fuses I mentioned were bad. (more specifically, check the connector/etc)